The Citânia de Briteiros is an Iron Age settlement built by the tribe of the Gallaecians in what is today Guimarães, Portugal. It is at the top of the hill of São Romão and it is one of the most important ancient settlements found in the Iberian Peninsula.
Around this site, evidence of Bronze Age occupation has been found, along with rock art and burial mounds. The houses are circular in shape, and ruins of a wall surrounding the settlement are present. The Citânia also contains a large circular building with benches around the walls, where the leaders would gather for an assembly - very similar to the Germanic Thing and the Spartan Apella.
The most impressive aspects of this settlement are its Pedras Formosas, or "Beautiful Stones" in English. Pedras Formosas are large engraved granite slabs found mainly in Northwestern Iberia. The oldest of them date as early as 1000 BCE and can weigh up to 5000 kilograms (11023 pounds). The main function of the Pedras Formosas were to separate the chambers in the public baths of these settlements, one having hot vapours and the other cold water. The Iberians of this region were known for their baths and saunas long before the Romans arrived, the Pedras Formosas and the public baths of these Iron Age settlements being proof of that.
The water was carried from conduits found in this site connected to a spring on the hill. Given the engravings and placement of some Pedras Formosas, it is thought they also served as monuments of some sort, possibly for rites of passage into adulthood.